I haven't seen anyone mention the element that parrotfish do have a lot of waste/excrement given the constantly eating/grazing nature. They are indeed beautiful and in some/many instances reef friendly - assuming they are well fed.
I would just do my homework (and you may absolutely have already done everything I certainly don't know) on making sure your water change plans and skimmer are up to the inevitable bioload a large parrot will bring. Ideally he is going to get very large and will only eat/waste more. It may be worth oversizing a skimmer early on so you aren't having to play catch up with levels later.
For what that is worth. Enjoy that beauty....